>If its possible to create a IP "Whitelist" for Reverse DNS will be greate, is it possible?
That should be as easy - just set up a local DNS server, configure reverse DNS entries for all your "whitelist"

Are you sure you want to? Some large email sites require some answer to DNS PTR queries before email is accepted - I am guessing that you are avoiding a significant amount of spam by the inclusion of the feature. Even my cable ISP has it together enough to have reverse DNS entries for all its IPs (including my own). Do you really want to accept mail from folks who are even more clueless than the average cable ISP?

To enable reverse DNS lookups or define an external DNS server list, complete the following steps:

1.
Start System Manager. If administrative groups are enabled, expand the administrative group in which the server you want to use is located.

2.
In the console tree, navigate to the Protocols container. Expand Servers, expand the server you want to work with, and then expand Protocols.

3.
In the console tree, expand SMTP. Right-click the virtual server that you want to work with, and then select Properties. The default SMTP virtual server controls message delivery for the default domain.

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

Disabling the Reverse DNS lookup makes email reception faster looks more friendly . I do use exchange not aware of Exim architecture but sure you will remain missing emails until you disable it . There are security reason/misconfigured some people don't allo the lookup one or other way .

I support the above comment to support the spam emails by putting resverse DNS lookup .

ADCs have gained traction within the last decade, largely due to increased demand for legacy load balancing appliances to handle more advanced application delivery requirements and improve application performance.

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